1. Field of the Invention
The present invention relates to a relay protection device for capacitor banks and preferably such capacitor banks as are used for series compensation in high voltage alternating networks.
2. Prior Art
In capacitor banks of the above-mentioned type there may occur disturbances of various kinds, such as unbalance voltages within the capacitor bank, overload on the network to which the capacitor is connected, flashover in a protective spark gap connected in parallel with the capacitor, flashover to the insulated platform on which the capacitor is placed, subharmonics, etc. For supervising such disturbances it may be economically justified to use fully insulated current transformers at voltages up to one or a few hundred kV. At successively increasing operating voltages of the AC networks, it is economically justified to use optronics for transmission of measurement values and signals from high voltage level to ground potential, but this technique of transmission is not accepted in some countries. It is considered complicated, difficult to modify and difficult to operate because of the requirements for special knowledge of the personnel who are to supervise the plant. This invention is therefore a complement to such optronics techniques in the form of an inexpensive electromagnetic link between high voltage and ground potential in capacitor banks.